In the popular product line of vehicles, after coating the vehicle body, the components are assembled to the body. In a coating step, with the door such as a front door or rear door separated from the body, the electrodeposition coatings are performed to the body and door, and temporarily attaching the door to the body, the second coating and finish coating are carried out to the body and door.
In such a case, in a subsequent assembling step, the door is detached and assembled to the body.
The door is bolted to the body when temporarily attached and assembled to the body, in which used for bolting is the fastening tool such as an impact wrench disclosed in JP H5-74770 U.
When fastening the bolt to the nut set in the body and temporarily attaching the door to the body, the flange formed at the bolt head has a contact with the door-side members having the electrodeposition coating film, whereby the coating film is shaved off and the shavings occur.
The nut arranged in the body also has the electrodeposition coating film, so that the bolt shaves the coating film, thereby causing the shavings.
Fastening the bolt in the nut is, for example, performed in such a way that the socket of the wrench covers and grips the bolt head, and the socket rotates. In the case, the shavings may occur by the contact of the socket with the bolt head.
Thus, when fastening the bolt using the fastening tool such as an impact wrench for attaching the door to the body, many shavings occur around the bolted portion.
On the other hand, in the coating step, in order to avoid the poor coating quality (e.g. seeding) caused by the coating such as second coating or finish coating with the dust adhered to the surface of the body or door, the coating operation is carried out in a clean environment such as in a clean room.
However, as mentioned above, the shavings occur when tacking the door to the body, and the shavings adhere to the surface of the body or door, which causes the imperfect coating such as the seeding in second coating or finish coating, so that it is preferable to avoid the adhesion of the shavings to the surfaces of the body and door when fastening the bolt in the nut for temporarily attaching the door to the body.